It is known to equip a motor vehicle with a system for monitoring the pressure of its tires. A pressure sensor is then placed in each tire. Each sensor is associated with a transmitter which sends the measured information to a central unit intended to process these data. Transmission is generally effected by a radiofrequency (RF transmission) with a frequency of 433 MHz. A single RF receiver is placed on the vehicle and collects the information dispatched by the transmitters so as to send them to the central unit.
Various, generally complex, processes are used to be able to determine for each item of information received the tire to which it corresponds. Document FR-2 774 178 discloses for example a process for locating and for recognizing the position of the wheels on a vehicle. Here, the wheels are each equipped with a sensor transmitting a detection signal representative of a state of the corresponding wheel. The vehicle is for its part equipped with a device for processing the detection signal. The process described in this document consists in determining a signature of a detection signal transmitted by a sensor carried by a wheel and in storing this signature and the corresponding position of the wheel in the processing device. Recognition of the position of a wheel is obtained by analyzing the signature of a detection signal and by comparing this signature with the stored signatures.
Such a process is difficult to implement. Furthermore, since the sensors are remote from the receiver, perturbations may disturb the sending of information and also the signature of the signal. It is also possible to have similar signatures which are difficult to differentiate. This is the case in particular when the receiver is arranged at the front of the vehicle and one wishes to distinguish the information coming from the rear left wheel from that originating from the rear right wheel.
Other processes of determination are known to the person skilled in the art. Without entering into details here, some of them require the presence of an LF (low frequency) link for communicating between the sensors and the receiver, others an inclinometer and/or an accelerometer at the level of each wheel.